Fatty acids are a class of carboxylic acids characterized as the saturated and unsaturated long chain acids commonly derived from natural fats and waxes. When obtained from natural sources, the compositions are generally mixtures containing varying amounts of individual fatty acid compounds and numerous minor components. Modern synthetic methods permit the manufacture of many of the natural compounds and their analogs, either as nearly pure single substances or as mixtures. For purposes of this application, the term fatty acid is intended to be inclusive of both natural and synthetic compounds, singly and in mixtures.
Fatty acids are widely used in the preparation of soaps, detergents, cosmetics and in certain formulations for gelling liquid hydrocarbon fuels. Manufacturing processes for many of the products often require that large volumes of fatty acids be transferred, and when the fatty acid is liquid at the ambient temperature or can be melted at a convenient temperature the transfer method of choice is pumping through tubing to the point of use. In formulations for the gelling of liquid hydrocarbons, transport of the fatty acid and rapid mixing to form solutions in the liquid hydrocarbon are made more practical when the fatty acid is liquid. Many of these gelling applications are intended to be used as continuous processes or in situations where the object is an extremely rapid gel formulation, and pumpability and fast mixing are prerequisites. One example of such an application is the use of fatty acids together with a caustic to gel and solidify aircraft fuel under emergency conditions, where the dispersion and dissolving of the fatty acid must occur extremely fast in order to be of any practical benefit. In these and similar gel-forming or thickening applications, the preferred fatty acids are liquid at the temperature ambient to the use, which confers the benefit of extremely rapid transfer and fast solubility.
Of the fatty acids readily available commercially, relatively few are liquid at the normal room temperature condition, and the number exhibiting pourability at the lower outdoor temperatures commonly encountered in a temperate climate are very few. Additionally, many of the natural sources of fatty acids have become increasingly limited in supply, and replacements have had to be found for many widely used commercial compositions such as the tall oils and the oleic acid mixtures, both of which are pourable liquids at relatively low temperatures. Recourse to synthetic sources has been less than satisfactory since very few synthetic mixtures exhibit pourability at usefully low temperatures.
Accordingly, a method for lowering the minimum pouring temperature of fatty acids would permit the use of a wider number of the available fatty acids in applications where pourability is a necessary and desirable characteristic. Additionally, in manufacturing processes employing fatty acids as starting materials, improving the pourability of the particular fatty acids employed could permit transfer under the ambient condition by pumping, thereby potentially improving process economics and in some instances effecting a saving in heat energy requirements.